Deferred Income Tax Assets And Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred Income Tax Assets And Liabilities [Line Items]
Net tax loss carryforwards	$ 1,146	$ 1,645
Operating Lease, Liability, Noncurrent	657	678
Accrued liabilities and deferred income	237	236
Tax credits	17	20
Depreciation and amortization	3	17
Provision for doubtful accounts	8	8
Other	110	75
Deferred Tax Assets, Valuation Allowance	204	214
Deferred Tax Assets, Net of Valuation Allowance	1,974	2,465
Operating Lease, Right-of-Use Asset	649	672
Depreciation and amortization	105	108
Deferred Tax Liabilities, Prepaid Expenses	8	17
Other	14	6
Deferred Tax Liabilities, Net	776	803
Deferred Tax Assets, Net	1,198	1,662
Deferred Income Tax Assets and Liabilities Additional Information (Detail) [Abstract]
Deferred Tax Assets, Valuation Allowance	204	214
Deferred Tax Assets Operating Loss Carryforward With Valuation Against It	195	192
Deferred Tax Assets State And Local	9	22
Vehicle Programs
Deferred Income Tax Assets And Liabilities [Line Items]
Depreciation and amortization	62	54
Depreciation and amortization	1,445	2,243
Other Assets [Member]
Deferred Income Tax Assets And Liabilities [Line Items]
Other	27	48
Other Liabilities [Member]
Deferred Income Tax Assets And Liabilities [Line Items]
Other	27	48
Liability [Member]
Deferred Income Tax Assets And Liabilities [Line Items]
Deferred Tax Liabilities, Net	1,472	2,291
Vehicle programs, net [Member]
Deferred Income Tax Assets And Liabilities [Line Items]
Deferred Tax Liabilities, Net	1,383	2,189
Deferred Tax Asset [Domain]
Deferred Income Tax Assets And Liabilities [Line Items]
Deferred Tax Assets, Net	$ 89	$ 102